Lapatinib (LAP) with trastuzumab (TRAS) plus an aromatase inhibitor (AI) may prolong progression-free survival (PFS) among women with HER2-positive, hormone receptor–positive metastatic breast cancer (MBC) compared with TRAS plus an AI, according to a study published in the Journal of Clinical Oncology.1
For the phase 3 ALTERNATIVE study (ClinicalTrials.gov Identifier: NCT01160211), researchers randomly assigned 355 patients to 1 of 3 treatment arms: LAP+TRAS+AI, TRAS+AI, or LAP+AI (patients received investigator’s choice of oral letrozole or anastrozole for the AI).
Patients in the LAP+TRAS+AI arm had a superior median PFS of 11.0 months compared with 5.7 months in the TRAS+AI arm (hazard ratio [HR], 0.62; 95% CI, 0.45-0.88; P = .0064); this PFS benefit was observed across all analyzed subgroups.
Patients treated with LAP+TRAS+AI also had an improved overall response rate (ORR) compared with patients in the TRAS+AI and LAP+AI groups (31.7% vs 13.7% and 18.6%, respectively), as well as clinical benefit rate (41% vs 31% and 33%).
The median PFS for LAP+AI vs TRAS+AI was 8.3 months vs 5.7 months, respectively (HR, 0.71; 95% CI, 0.51-0.98; P = .0361).
The most frequently reported adverse events (AEs) across the 3 treatment arms included diarrhea, rash, nausea, and paronychia, most of which were grade 1 or 2.
The treatments arms that received LAP, however, had a higher AE rate than the TRAS+AI arm.
The authors concluded that “this combination can potentially offer an effective and well-tolerated, chemotherapy-sparing alternative treatment regimen for patients for whom chemotherapy is not intended.”
- Johnston SR, Hegg R, Im SA, et al. Phase III, randomized study of dual human epidermal growth factor receptor 2 (HER2) blockade with lapatinib plus trastuzumab in combination with an aromatase inhibitor in postmenopausal women with HER2-positive, hormone receptor-positive metastatic breast cancer: ALTERNATIVE. J Clin Oncol. 2017 Dec 15. doi: 10.1200/JCO.2017.74.7824 [Epub ahead of print]